A choke valve of a clutch release cylinder serves to prevent a sudden discharge of actuating oil when the clutch pedal is released to enable a smooth power connection of the clutch.
When the clutch pedal is depressed, resistance of the choke valve in relation to the actuating oil flow is preferably small so that the actuating oil can be smoothly and swiftly supplied into the clutch release cylinder, while minimizing vibration and noise. When the actuating oil is discharged, the choke valve should function properly for the actuating oil to be slowly returned.